Category Homebrew

70cm bicycle antenna

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During the summer season I sometimes travel to work by bike. It’s a 21 km trip through the countryside, passing cornfields, orchards, deer and spoonbills. The road includes dikes and bridges, and even a ferry to cross one of the…

PC6REC ATV station

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During the 2014 edition of the REC Fielddays I facilitated a live videofeed,  broadcasted throughout the Netherlands. Using three cameras and a bunch of (mostly) vintage hardware, the live stream was uplinked to the local ATV repeater PI6ATV. Viewers could…

Stereo to mono converter

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My TV camera generates stereo audio, like most cameras do. However, my local ATV repeater only supports mono audio. So to transmit a nice audio signal with my TV pictures, I needed a way to convert the stereo signal to…

PoRG v2

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A couple of years ago I built my first PoRG (abbreviation for “Power over RG-cable”), a simple phantom power supply to power some device over antenna cable (e.g. a preamp, active antenna, coax switch, etc). I recently built an active antenna…

A very small active antenna

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Small active antennas like the “mini-whip” (by PA0RDT) are very popular at the moment. They provide good reception of signals from HF all the way down to the VLF band. Here in the Netherlands Van Dijken Elektronica sells a nice…

The “PoRG”

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The “PoRG” is a very simple but useful device in your ham shack. “PoRG” is an abbreviation for “Power over RG-cable” and allows you to put DC on your antenna cable. Some people call it a phantom power supply. With…

CLog 0.9b released

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Today I released CLog version 0.9b, the command-line hamradio logbook. Although still beta, the software appears to be reliable now, even when used in multi-operator contests. These are the changes in CLog 0.9b:

HB9CV-in-a-box antenna for 23cm

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The HB9CV has been a popular antenna for decades, especially on the 2m band where it is commonly used for direction finding (foxhunt). Others create arrays of HB9CV antennas for DXing. Since I needed a simple antenna for 23cm (to…

First ATV transmission

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I’m working on a 23cm ATV transmitter. A couple of years ago I already bought some modules from PE1ACB: a baseband modulator, a 23cm ATV transmitter (output 1 watt) and a controller unit. Today I hooked up all modules, together…

Spijkerradio

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Introduction “Spijker” is a dutch word for nail, which you would normally use to hang something on the wall, or to construct wooden stuff. However, (brass) nails can also be used as as solder pad. PA0KLS used this idea to…

J-pole antennas for HF bands

Introduction I’ve been using J-pole antennas on the 2m band from the first day I got licensed. They perform very well, are easy to construct and are cheap. Since Adrian PA0RDA and I have been experimenting with vertical antennas for…

Squalo antenna for 6m

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Introduction Adri PA0RDA, a friend of me, is trying to do some DX on 6m for a while now. His antenna position is very poor: he lives in the bottom flat of a 5-floor building. He has a balcony on…

Arrow antenna

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Introduction The arrow antenna is a popular antenna for using FM transponders on satellites. These satellites have a uplink on the 2m band, and a downlink on 70cm. You can operate those satellites with a simple dualband handheld radio.

TNC-X

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Introduction The Dutch Amateur Radio Emergency Service (DARES) is currently setting up a messaging system for emergency communications. Email is sent over radio using the good old AX.25 protocol. Part of this project is the TNC-X, a simple packet radio…

HEDZ antenna for 80 and 160m

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Introduction The zeppelin antenna (or simply “zepp”) is a popular end-fed wire antenna for shortwave bands and has lots of simularities with the J-pole antenna. It consists of a long wire (half wave length), connected to one of the wires…